1. Field of the Invention
The present invention relates to a capsule endoscope system for observing the inside of a subject with a capsule endoscope introduced into the subject mounted on a mounting bed, an in-vivo information acquiring apparatus and the capsule endoscope for acquiring an internal image(s) of an organ imaged by the capsule endoscope introduced into the subject.
2. Description of the Related Art
In recent years, in the field of endoscopes, a capsule endoscope including an imaging function and a wireless communication function has appeared. The capsule endoscope is swallowed from a mouth of an examined person as a subject (human body) for observation (examination). After this, the capsule endoscope moves inside organs (body cavity) such as the esophagus, stomach, and small intestine by peristaltic movement of the organs, and sequentially performs imaging using the imaging function during an observation period until the capsule endoscope is naturally discharged from the living body of the subject.
For example, Japanese Patent Application Laid-Open Nos. 7-289504, 2004-298560, 2004-121837 and 2002-65765 disclose techniques as systems utilizing this type of capsule endoscope. Each of the systems has a gravity sensor installed in the capsule endoscope so as to detect the gravity direction. The system determines the luminal direction based on an endoscope image imaged by the capsule endoscope. The system inclines a bed in such a manner that the luminal direction agrees with the gravity direction. As a result, the system observes the subject while the physical position of the subject on the bed is inclined and the capsule endoscope is moved in the gravity direction.
This type of capsule endoscope sequentially images the internal image of the organ (hereinafter, sometimes referred to as an internal image of the subject) at an interval of, for example, 0.5 second in time series. The capsule endoscope in the subject sequentially and wirelessly sends the imaged internal image of the organ to a receiving device outside the subject.
This receiving device is attached onto the subject and acquires the internal images of the subject imaged by the capsule endoscope inside the subject while the capsule endoscope moves inside the subject. In this case, stick-on type receiving antennas are attached onto a plurality of spots (e.g. eight spots) on the body surface of the subject. The plurality of receiving antennas are connected to the receiving device carried by the subject through a cable or the like. This receiving device receives a wireless signal from the capsule endoscope through the plurality of receiving antennas, and acquires the internal images of the subject included in the received wireless signal.
A portable recording medium is detachably attached to the receiving device. The storage medium attached to the receiving device sequentially stores the internal images of the subject received by the receiving device from the capsule endoscope in the subject. After that, the storage medium having stored a group of internal images of the subject is removed from the receiving device and attached to a predetermined image display device.
The image display device having the storage medium attached thereinto reads the group of internal images of the subject stored on the storage medium, and displays the group of read internal images of the subject. In this case, a user (such as a doctor, or a nurse) controls the image display device to sequentially display the group of internal images of the subject thereon in time series. As a result, the user can observe (examine) the inside of the organ of the subject, and can diagnose the subject (see, for example, Japanese Patent Application Laid-Open No. 2003-19111).
This type of capsule endoscope includes a hook member that freely slides in and out and projects from a capsule casing so as to hook on the internal wall of the organ, or an expansion member that expands expandably and contractibly from the capsule casing so as to hook on the internal wall of the organ (see, for example, Japanese Patent Application Laid-Open No. 2004-440). This capsule endoscope is orally taken into the subject, and then sequentially moves along the organs inside the subject. When the endoscope reaches a particular examined region in the subject, the hook member or the expansion member hooks and stops on the internal wall of the organ. Because the capsule endoscope stops in the particular examined region, the capsule endoscope can precisely image the particular examined region.
This capsule endoscope may have a specific gravity set equal to or lower than 1 so as to image the internal image of the organ that the capsule endoscope floats on the water surface inside the organ of the subject. In this case, the capsule endoscope includes a floating member in place of the above-described hook member or expansion member, and has a specific gravity that becomes equal to or lower than 1 when the floating member expands.
Like the expansion member of the capsule endoscope disclosed in Patent Document 6, the floating member may be contained inside the casing so as to expand expandably and contractibly from the casing, or may be arranged outside the casing. The capsule endoscope may include, inside the casing, a space with a predetermined volume or larger so as to set the specific gravity of the capsule endoscope equal to or lower than 1.